<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>dom</title>
	<style type="text/css">
		.box{
			width: 200px;
			height: 200px;
			background: red url() 0 0 no-repeat;
		}
		.box1{
			width: 200px;
			height: 200px;
			background: blue url() 0 0 no-repeat;
		}
	</style>

	<script type="text/javascript">
		 window.onload =function  (argument) {
		 	var box = document.getElementsByClassName('box');

		 	// alert(box);

			box[0].onclick = function  () {
			 	
			}
		 }
	</script>

</head>
<body>

	<div class="box" id="box" name='box'></div>
	<div class="box1"></div>


</body>
</html>